Generally, for example, a condenser, an evaporator and an intercooler as a heat exchanger for motor vehicles are manufactured by brazing a tube material or a plate material having a shape including a fluid passage, and a corrugated fin material, with the materials alternately superposed and combined. The tube material, the plate material and the fin material are formed from a brazing aluminum alloy material or an aluminum alloy brazing sheet which is fabricated by cladding an Al—Si-based filler alloy or the like on one side or both sides of a core material made of an aluminum alloy.
Al—Mn-based alloys have been predominantly used for a conventional brazing aluminum alloy material and a conventional core material for an aluminum alloy brazing sheet. In order to enhance the strength of the aluminum alloy, a brazing aluminum alloy material with Cu, and Si or Mg added, and an aluminum alloy brazing sheet fabricated by cladding an Al—Si-based filler alloy on a core material using the brazing aluminum alloy material have been proposed (For example, see Patent Documents 1 to 3).
Patent Document 1: Japanese Patent Application Laid-Open No. 8-291353 (Paragraphs 0010 to 0015 and 0025)
Patent Document 2: Japanese Patent Application Laid-Open No. 5-339666 (Paragraphs 0005 to 0013)
Patent Document 3: Japanese Patent Application Laid-Open No. 4-202735 (page 2, upper-right column, line 12 to page 2, lower-left column, line 17)